AppJet (→ Etherpad), YC Founder Story

Company: AppJet, Inc. (pivoted to → Etherpad) Founders: Aaron Iba (CEO), J.D. Zamfirescu (CTO), David Greenspan, Daniel Clemens YC Batch: Summer 2007 (S07) Industry: Developer Tools → Real-Time Collaboration Founded: 2007 | Acquired by Google: December 2009 Acquisition Price: Low eight figures (~$10M+) Legacy: Etherpad's open-source codebase lives on in Google Docs, Notion, and dozens of modern collaboration tools to this day

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The One-Line Summary

Three ex-Google engineers left stable, prestigious jobs to build a developer platform nobody used, then accidentally invented real-time collaborative editing on a Friday afternoon, watched that side project become the real company, and got acquired by Google two years later. The thing they built to demo the product they failed at became one of the most influential pieces of software infrastructure in the modern internet.

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Lens 1, The Before State

Who Were They Before YC?

Aaron Iba, J.D. Zamfirescu, and David Greenspan were not struggling outsiders who needed a break. They were engineers at Google's Search Quality team, one of the most prestigious and technically demanding groups inside one of the most coveted companies in Silicon Valley. They had graduated from MIT. They had won programming competitions. Aaron had won MIT's Battlecode competition in 2003. These were the kinds of people who didn't need to take a risk, the system had already rewarded them.

Aaron left Google in March 2007. J.D. followed in October 2007. They moved to Cambridge, Massachusetts, and began building AppJet.

The decision to leave Google was not driven by financial desperation or a burning itch for wealth. It was driven by something harder to name: a sense that the most interesting technical problems weren't inside large companies. They wanted to build from scratch. They wanted to feel what it was like to create something from zero and put it in front of the world.

The Personal Frustration They Were Solving

The original AppJet idea came from a classic developer pain point: deploying web apps was unnecessarily complicated. In 2007, if you wanted to build and host a web application, you had to configure servers, manage infrastructure, deal with databases, understand deployment pipelines, a stack of complexity that stood between an idea and a live product on the internet.

Their insight: what if you could build and host a web app entirely in the browser, in JavaScript, with zero server configuration? Just open a URL, write code, and your app is live. They wanted to be, as YC partner Alexis Ohanian later described it, Rails and Heroku at the same time, before either of those products was dominant.

Why They Almost Couldn't See Their Own Pivot Coming

Here's the psychological trap they were in: they had spent over a year building something technically impressive. The AppJet platform was genuinely sophisticated, it had server-side JavaScript execution, a built-in editor, database support, even a Facebook API integration layer. These were smart engineers who had built something real.

And almost nobody was using it.

Aaron later wrote on Hacker News with stark honesty: "AppJet was a failing idea. We had like no users. We had spent over a year building this developer platform and we had practically zero developers actually using it. It clearly wasn't working."

The hardest thing for technically excellent founders to do is admit that excellent engineering is not the same as a product people want. The AppJet founders had to learn that the hard way, and then be humble and alert enough to spot the pivot opportunity when it appeared, quietly, as a Friday afternoon demo.

Key Insight for Aspiring Founders

Competence at building does not guarantee that you're building the right thing. Three MIT-trained ex-Google engineers spent a year building something technically impressive that nobody used. The lesson isn't that they were wrong to try, it's that they stayed alert, honest, and humble enough to recognise when a side project was showing more life than the main product. That alertness is a skill most founders never develop.

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Lens 2, The Idea Origin

The Main Idea, AppJet

The original AppJet concept was simple and legitimate: make web app development accessible to anyone who could write JavaScript. Run the code server-side. Host it automatically. Let a developer go from idea to live product in a single browser session with no infrastructure knowledge required.

They built it. It was real. It launched publicly on December 12, 2007. They had the YC backing, a working product, and a clear value proposition. And developers just... didn't show up in any meaningful numbers.

Part of the problem, as Ohanian described it, was ambition scope: they were trying to solve both the framework problem and the hosting problem simultaneously. For a small team on YC funding, this was too much surface area. The product was impressive but the adoption curve was flat.

The Accidental Idea, Etherpad

This is where the story gets extraordinary.

At some point during their building of AppJet, the team wanted to demonstrate what their platform could do. The most compelling demo they could imagine: what if multiple people could edit the same document at the same time, and see each other's keystrokes appear in real-time, with no delay?

They built this demo, not as a product, not as a pivot, but as a proof-of-concept for AppJet's underlying runtime. It was, in the language of that era, a Friday afternoon project.

The technical challenge they solved was one of the hardest in distributed systems: Operational Transformation (OT), the algorithm that reconciles simultaneous edits from multiple users without creating conflicts or data loss. Google Docs at the time updated every 15 seconds, creating a noticeable lag that disrupted collaboration. The AppJet team built something that updated every half second, a 30x improvement, making the experience feel genuinely live.

They called this demo Etherpad. They launched it publicly on November 19, 2008.

The Signal That Validated the Pivot

Within days of public launch, the usage was unlike anything they'd seen with AppJet. Etherpad started spreading through the exact communities where AppJet had failed to get traction, developers, writers, newsrooms, student groups. Wikipedia editors were using it. NPR journalists were using it. Mozilla engineers were using it for collaborative documentation.

Aaron's own words on Hacker News capture the moment: "We were ecstatic when Etherpad took off. After Etherpad took off, we shut down appjet.com and focused our entire company on Etherpad. appjet.com redirected to etherpad.com. It felt great to have a product that people were actually using."

They had paying customers. They had thousands of dollars a month in revenue. The direction was clear. They shut down AppJet and became an Etherpad company.

The Pattern This Follows

AppJet/Etherpad is one of the cleanest examples of a YC pivot archetype: a technically strong team builds the wrong product, builds an internal tool to support the wrong product, and the internal tool turns out to be the right product. This same pattern appears in Slack (pivot from a game called Glitch), YouTube (pivot from a dating site), and Instagram (pivot from a location check-in app called Burbn).

The common thread: the best product is often hiding inside the thing you're actually using to build the other thing.